1. Field of the Invention
The present invention relates to an electrophotographic image-receiving sheet and an image-forming process, especially to an electrophotographic image-receiving sheet with substantially improved long-run properties suitable for use in fixing belt electrophotography, and to an image-forming process which employs the electrophotographic image-receiving sheet.
2. Description of the Related Art
In dry treatment, the electrophotography method has quick printing speed and is the printing method currently used for copiers or the output device of a personal computer. This electrophotography method transfers a toner image to an image-receiving sheet, passes this through a fixing part which is heated and/or pressurized, for example, a fixing roller or a fixing belt, and fixes the toner image onto an image-receiving sheet. To improve gloss and to approach the appearance of a photograph, it has been proposed that this image-receiving sheet, in addition to a general-purpose paper (regular paper, paper of fine quality, or the like), may be an image-receiving material for electrophotography which has a toner image-receiving layer containing a thermoplastic resin on a support (Japanese Patent Application Laid-Open (JP-A) Nos. 04-212168, 08-211645, or the like). In order to prevent offset when the image-receiving material peels away from the aforesaid fixing part in such a toner image-receiving layer, to prevent cracks in the toner image-receiving layer and to improve the quality of the image, it has been proposed to add a wax which has a given release effect (Japanese Patent Application Laid-Open (JP-A) Nos. 11-52604, 11-52605, 11-52606 and 11-212292, or the like).
However, the amount of releasing agent in the related art is optimized for the fixing roller electrophotography method, and the amount required by the image-receiving sheet used by the fixing belt electrophotography method does not necessarily correspond. That is, in the fixing roller electrophotography method, the image-receiving sheet separates from the fixing roller immediately after being heated by the fixing roller. Therefore, in order to improve the releasing characteristic of the fixing roller from image-receiving sheet, a large amount of releasing agent was added to the layer comprising the surface of the image-receiving sheet which comes in contact with the fixing roller, as described in JP-A No. 11-212292.
Moreover, in the aforementioned fixing belt electrophotography method, a surface of the image-receiving sheet and the surface of the fixing belt must be in intimate contact, while the image-receiving sheet is transported on the fixing part. Thus, if the releasing characteristic between the fixing belt as a fixing part and the image-receiving sheet is high, problems arise. This is because, in the fixing belt electrophotography method, a glossy image is not obtained if the fixing belt and the image-receiving sheet are not in contact while being transported in the fixing part. Therefore, it is necessary to adjust the releasing characteristic of the fixing belt and image-receiving sheet to an extent which brings them into suitable contact while being transported the fixing part, and allows them to separate without causing an offset when the image-receiving sheet is released from the fixing belt. It is also necessary to optimize the amount of the releasing agent added to the layer forming the surface of the image-receiving sheet which comes in contact with the fixing belt in the fixing belt electrophotography method.